Being overweight ‘ages the brain’

Scientists have discovered another crucial reason why it is important to maintain a healthy physique.

Researchers at the University of Cambridge in the U.K. claim that the brains of overweight and obese people can appear much older than those of healthy, lean people.

The research team studied data from 473 healthy individuals between 20 and 87 years old, who were recruited from the Cambridge Centre for Ageing and Neuroscience.

They divided the participants into two categories based on weight and conducted MRI scans of the participants' brains. Using special computer software, they were able to generate measures of whole brain cerebral white matter volume, cortical thickness and surface area. White matter is the tissue that connects different areas of the brain and allows for information to be communicated between regions.

Interestingly, when the researchers analysed the data, they found striking differences in the volume of white matter - overweight and obese people had a widespread reduction of white matter when compared to lean people.

The researchers then calculated how white matter volume related to age across the two groups. They discovered that an overweight or obese person had a similar amount of white matter as a lean person 10 years their senior. For example, a 40-year-old obese person has a similar amount of white matter as a 50-year-old lean person. Strikingly, this observation was noted especially in middle age participants, suggesting that our brains may be “particularly vulnerable” during this period of ageing.

"As our brains age, they naturally shrink in size, but it isn't clear why people who are overweight have a greater reduction in the amount of white matter," said Dr Lisa Ronan. "We can only speculate on whether obesity might in some way cause these changes or whether obesity is a consequence of brain changes."

While senior author Professor Paul Fletcher added that it was important that further investigation be taken into the topic.

"We're living in an ageing population, with increasing levels of obesity, so it's essential that we establish how these two factors might interact, since the consequences for health are potentially serious,” he said.

Despite the clear differences in the volume of white matter between lean and overweight individuals, the researchers found no connection between being overweight or obese and an individual's cognitive abilities, as measured using a standard test similar to an IQ test.